«Lira» geometry
A curved section with a flat baffle and an elliptical back. It removes parallel walls, spreads the internal resonant modes and breaks up standing waves.
First series in preparation
450 interestedOpus I
A two-way loudspeaker built on one simple idea: put acoustic behaviour ahead of what mass production allows.
Drivers byBeymaKeep me posted
Inside the model
Interact with the Opus using your mouse
This is the actual CAD model the workshop DXFs come from: 120 parts, each with its place and its assembly order. Spin it, open it step by step and tap any part to see what it does and why it matters for the sound.
Project status
Where the Opus I stands today
01Concept and acoustic designComplete
Deciding what the loudspeaker had to get right before drawing anything, choosing the drivers and taking the system into simulation.
Defining the project4/4
- Design goals: minimum distortion and progressive directivityDone
- Review of the technical literature (AES, JAES, Toole and Olive, Linkwitz, Geddes, Klippel)Done
- Choosing the configuration: a two-way bass-reflex bookshelfDone
- Deciding on the kit format as the philosophy of the projectDone
Choosing the drivers4/4
- Comparison of manufacturers and rangesDone
- Choosing the Beyma NMF series: 8NMFW woofer and T25M tweeterDone
- Contact with Beyma engineering and validation of the approachDone
- Transferring the Thiele-Small parameters from the datasheetsDone
Electroacoustic simulation4/4
- Modelling the cabinet and calculating the internal volumeDone
- Calculating the bass-reflex port tuningDone
- Study of baffle diffraction and the baffle stepDone
- Simulation project set up with the real woofer impedanceDone
02The «Lira» cabinetComplete
The cabinet: curved geometry with no parallel walls, a 40 mm laminated body and every manufacturing drawing generated from a parametric 3D model.
Geometry4/4
- Curved section with a flat baffle and an elliptical backDone
- Removal of the internal parallel wallsDone
- Rebates so the drivers sit flush with the baffleDone
- Bass-reflex port milled into the wooden slices themselvesDone
Laminated construction4/4
- Stacking the 23 layers of the bodyDone
- A 40 mm front wall, and 30 mm side and rear wallsDone
- Vertical compression with four M8 threaded rodsDone
- Captive hex nut in the bottom plate so the rod cannot turnDone
3D modelling and manufacturing drawings5/5
- Parametric 3D model of the whole cabinetDone
- Numerical verification of volume and tuning on the modelDone
- Slice-by-slice breakdown, numberedDone
- Generation of the full set of CNC cutting filesDone
- Renders and previews of the assembled cabinetDone
Construction details4/4
- Custom rear terminal plate, flush with the back of the cabinetDone
- 3 mm top plate set into the lid (black acrylic on the prototype)Done
- Bolted, removable baffle with a butyl sealDone
- Final engraving of the top plateDone
03CrossoverComplete
Matching the crossover to the Beyma drivers to get everything out of them, settling the components and taking it from schematic to manufactured board.
Crossover design6/6
- Fourth-order low-pass for the wooferDone
- Zobel network for impedance compensationDone
- Second-order high-pass for the tweeterDone
- Notch filter to smooth the tweeter peakDone
- L-pad attenuator with a bypass on the top octaveDone
- Schematic validated by Beyma engineeringDone
Components and suppliers6/6
- Air-core coils, with no core that can saturateDone
- Jantzen Audio polypropylene capacitors and resistorsDone
- Dayton Audio main coil and binding postsDone
- Supplier settled: distribution from the Netherlands (SoundImports)Done
- Production prices settled for the first seriesDone
- Bill of materials published openlyDone
Board engineering7/7
- KiCad schematic, passing electrical checks with no errorsDone
- Wiring checked point by pointDone
- Board shaped like the lyre outline, so it fits through the woofer cutoutDone
- Coils mounted on edge to avoid magnetic coupling between themDone
- Final boards received from the factory: 1.6 mm FR4 with 2 oz copper, silkscreened with every component footprintDone
- Full-size check with the components laid on the printed boardDone
- Seven mounting points verified against the cabinet woodDone
Assembly and validation5/5
- Crossover assembled and values checked part by partDone
- Bi-amping jumpers verifiedDone
- First listening session with the final crossoverDone
- Crossover assembly document writtenDone
- Tweeter polarity measured and settledDone
04Prototypes and iterationComplete
Build, listen, write down everything that did not fit and draw it again. That is where the current design came from, now in high-precision machining.
First prototype in the home workshop4/4
- Gluing the laminated bodyDone
- Machining the baffle and the driver rebatesDone
- Fitting the drivers and the internal wiringDone
- First listening session with the complete systemDone
Design iteration and improvements7/7
- Correcting the gluing tolerances that threw the baffle out of squareDone
- Port redesigned as a through cut, cleaner and more robustDone
- Rod system solved: they neither turn nor split the woodDone
- Internal volume and tuning adjusted on the real modelDone
- Baffle bolted into barrel nuts, and an unglued body: the layers seal dryDone
- Materials and fasteners optimisedDone
- Greater manufacturing precision in the cutting setDone
Assembly testing and validation3/3
- Numbered parts that only fit one wayDone
- Timed build: about two hours per pair of cabinetsDone
- Confirmation that no special tools are neededDone
v11 prototype with high-precision CNC6/6
- Workshop chosen: Nord Taller, digital craftsmen in Vilafranca del PenedèsDone
- 19 mm MDF board, thicknessed to exact sizeDone
- Final cutting files prepared and deliveredDone
- Machining the partsDone
- Dimensional check and prototype assemblyDone
- Listening to and validating the final prototypeDone
05Measurements and acoustic validation9 of 11
The first measurements are done and published. What is missing is someone outside, with an anechoic chamber, confirming them.
Preliminary measurements6/6
- Woofer impedance in free air, in a sealed box and with the port openDone
- Reading the real port tuning off the impedance curveDone
- On-axis frequency response, measured at one metreDone
- Off-axis response at 45, 90 and 120 degreesDone
- Impedance of the complete system with the crossover fittedDone
- Plots and their interpretation published on this same pageDone
External validation3/5
- Measurement protocol writtenDone
- A laboratory to validate the measurements: Beyma’s semi-anechoic chamberDone
- Measurement of one v11 prototype unit in Beyma’s chamber (8 October 2026)NewDone
- Full directivity set, Spinorama styleTo do
- Blind comparative listening against reference monitorsTo do
06Finishes, packaging and production7 of 12
Turning a prototype into something that can be manufactured, finished and sent to someone’s home without arriving damaged.
Look and finishes3/5
- First visual previews and finish simulationsDone
- Decision on the lacquered variantDone
- Choosing the lacquering workshopIn progress
- Lacquering the first pairTo do
- Final finish: white lacquer with a black baffleDone
Packaging and shipping3/5
- Real weights calculated, part by partDone
- Shipment split into four packages per pair, none over 15 kgDone
- First double-wall cardboard supplier consultedDone
- Looking into packaging systems and die-cut protective traysIn progress
- Settling the carrier and shipping ratesIn progress
Kit documentation1/2
- Illustrated assembly manual, in Spanish and CatalanDone
- Step-by-step assembly videos, reachable by QR codeTo do
07Presentation and public release7 of 10
The project has been told in the open from day one. What is left is playing it in front of people and opening the first series.
Telling the project4/4
- Public Opus I page on HifiCaféDone
- Series of process videos on the YouTube channelDone
- Opus I community group openedDone
- List of people interested in the listening sessionsDone
First public listening session3/3
- Looking for a room in BarcelonaDone
- Presentation at the Stereo Vintage Barcelona fair (September 2026)Done
- Date and format confirmedDone
Opening the first series0/3
- Final price and termsIn progress
- Reservations for the first numbered seriesTo do
- First deliveriesTo do
The method
Loudspeaker design stopped depending on mysticism and intuition decades ago. Today there are simulation tools, analysis systems and a large body of literature that let you predict precisely how each decision affects the final result. The Opus I applies that accumulated knowledge.
Development focused on two critical goals:
- Reduce system distortion. Both the non-linearity of the drivers themselves and the acoustic and mechanical colouration the cabinet adds.
- Optimise the angular response. A balanced on-axis frequency response combined with progressive off-axis directivity. The work of Floyd Toole and Sean Olive shows that this correlation is the key factor in listener preference in blind tests.
That does not mean there is one correct sound: certain physical behaviours are statistically preferred because they cause less listening fatigue and stay closer to the original message.
The kit format as a philosophy. The kit brings back the audio culture of the sixties and seventies: building it is not only cheaper, it is how you get to understand the loudspeaker from the inside. The cabinet is not glued: the 23 layers are held by four threaded rods, and it can be opened and closed again. The drivers are from Beyma, who design and manufacture in Moncada (Valencia).
The design of the first series is fixed. One unit of the v11 prototype was measured on 8 October 2026 in Beyma’s semi-anechoic chamber, and the response, sensitivity, impedance and distortion figures on this page come from that measurement. Still to come: directivity beyond the 30° already measured, blind comparative listening against reference monitors on the market, and some fine adjustments, such as the port tuning.
Construction
Why it is built this way
Every geometric and material decision balances acoustic performance against what can realistically be assembled at home. The design is meant to make the result depend on the project, not on the previous skill of whoever builds it.
See the 9 construction points
A 23-layer body
A structure made of 23 CNC-machined layers of 19 mm MDF. The front wall is 40 mm thick, the side and rear walls 30 mm. The layers are not glued: they are stacked and compressed, and the joints seal dry.
Vertical compression
Four M8 steel threaded rods run through the body from top to bottom and keep it under pressure. They hold the layers without glue, so the cabinet can be opened and closed again.
Integrated bass-reflex port
The tuning duct is milled straight into the wooden slices themselves. It avoids the tube resonances of commercial plastic ports and keeps the tuning dimensionally exact.
Professional Beyma drivers
An 8NMFW woofer (carbon cone) and a T25M dome tweeter. Professional-grade components, chosen for their low dynamic compression and thermal stability at high sound pressure.
Flush-mounted baffle
Both drivers sit flush with the baffle in micrometric rebates. This minimises edge diffraction at the front.
Guided assembly, no mistakes
The layers arrive numbered, except the base, and slide down the four rods in the marked order. All the M4 screws take a single 3 mm Allen key.
Jantzen + Dayton crossover
A passive crossover with air-core coils (no core to saturate) and polypropylene capacitors from Jantzen Audio and Dayton Audio. It includes impedance-correction and attenuation networks calculated for a clean transition between ways.
Specific details
A custom rear terminal plate, laser-cut and engraved in 4 mm black acrylic, with four binding posts for bi-wiring. It sits flush in a rebate at the back of the cabinet.
Foundations
The science behind it
The Opus I is not based on esoterics; it rests on technical literature verified in primary sources (AES, JAES, BBC Research). The core references for the design are:
See the sources
Electroacoustic modelling
- Thiele-Small · Leo Beranek · Harry OlsonSystem parameters and the classic treatises on diffraction
Perception and directivity
- Floyd Toole · Sean Olive · Allan DevantierSpinorama (CTA-2034), directivity and preference prediction models
Non-linear behaviour
- Earl Geddes · Wolfgang KlippelModern distortion analysis
Crossovers and filters
- Siegfried LinkwitzDispersion networks and filters
Simulation and measurement
- VituixCAD · Hornresp · REWDesign optimisation and experimental measurement
The brands mentioned belong to their owners and appear only as a technical reference.
Crossover
The crossover
The crossover is the brain of the loudspeaker: it splits the signal coming from the amplifier between woofer and tweeter, sending each driver only the band it can reproduce and protecting it from the one that would damage it. But it does more than «cut»: it corrects the frequency response, matches the levels of the two drivers, compensates their impedances and aligns their phase so both sound like a single coherent source. That is why a well-designed crossover is the difference between a loudspeaker that measures well and one that also sounds natural. And the maths is not enough without good materials: air-core coils (no core to saturate), low-loss polypropylene capacitors and non-inductive power resistors keep the signal clean, stable at high volume and faithful over time. In the Opus I the crossover is passive, built from Jantzen Audio and Dayton Audio parts, measured piece by piece and mounted on a printed circuit board shaped like the cabinet itself.
See the schematic and the component detail
Functional blocks
Woofer low-pass
L1 · L2 · C1 · C2 · R1The two series coils (L1 1.5 mH and L2 0.8 mH) let the bass through to the 8NMFW and progressively hold back the treble. Capacitors C1 (22 µF) and C2 (4.7 µF) shunt what is left over to ground, and R1 (1.8 Ω) damps that network so the cut is clean and free of resonances.
Impedance compensation (Zobel)
C3 · R2C3 (22 µF) in series with R2 (18 Ω) forms a Zobel network at the woofer input. It corrects the impedance rise caused by voice-coil inductance, so the low-pass filter «sees» a stable, resistive load and works exactly as calculated.
Tweeter high-pass
C4 · L3C4 (8.2 µF) in series with L3 (0.55 mH) to ground forms a 2nd-order high-pass (12 dB/oct). It blocks the bass that would damage the T25M and passes only the top band it can reproduce.
Notch filter
L4 · C5 · C6 · R3L4 (0.7 mH) with C5 (1.5 µF) and C6 (1 µF) forms a series resonant network to ground that «sucks out» a specific peak in the tweeter response. R3 (4.7 Ω) sets the depth and Q of that trap, smoothing the curve without overdoing it.
L-pad attenuator + bypass
R5 · R4 · C7R5 (3.3 Ω) in series and R4 (12 Ω) in parallel form an L-pad: they bring the tweeter level down to match the woofer sensitivity while keeping the impedance seen by the crossover constant. C7 (3.3 µF) bypasses R5 at the top end so the last octave keeps its air and sparkle.
Components
Beyma drivers
Both drivers in the Opus I come from Beyma’s NMF (Near & Mid Field) series: a new high-end range the Valencian manufacturer designed specifically for near and mid field —domestic high fidelity and recording studios. Developed over two years of multiphysics simulation in search of extreme linearity and minimal distortion, Beyma sums it up as «live sound at home».
Why Beyma
Choosing the drivers is the decision that shapes a two-way design most: they are what moves the air. After comparing several brands, the drivers in the Opus I are Beyma, and not for a single reason.
Driver quality
Professional-grade components, not consumer catalogue parts. The NMF series comes out of two years of multiphysics simulation chasing linearity and minimal distortion: an honest base to build a good loudspeaker on.
More than half a century of history
Founded in 1969, Beyma is today one of the reference brands in professional audio in Europe. Behind every driver there are fifty years of accumulated craft.
Reliable and rugged
Born for professional sound —tours, venues, studios— they take far more than you will ever ask of them at home. That ruggedness turns into peace of mind: a loudspeaker for years.
A Spanish company
They design and manufacture in Moncada, Valencia. Working with a local manufacturer shortens distances and lead times, and keeps the project close to home.
Professionalism and decency
In every contact, from engineering to sales, the same seriousness and the same good treatment. It is a pleasure to work with people like that.
But if I have to keep one reason above all the rest, it is the most human one: with Beyma you can talk. You pick up the phone and on the other end there are engineers, designers and a sales and communication team willing to discuss, to explain what you ask and to listen to what you propose. It is not a closed catalogue or a form that never gets answered. We are all people —and in the end, this is made by people for people.
Josep Maria Marimon
Get to know Beyma and its drivers
Beyma was founded in 1969, when the Masip family moved from Barcelona to Valencia to build loudspeakers. It designs and produces at its facilities in Moncada (Valencia). In 1974 it took its products to the Musikmesse fair in Frankfurt, and since 1976 it has exported across Europe; more than fifty years later it is one of the reference brands in professional audio.
The two drivers in the Opus I
Beyma 8NMFW
8″ woofer · low-mid
- Diameter
- 200 mm · 8″
- Impedance
- 8 Ω · minimum 7.4 Ω
- Power
- 200 W AES
- Cone
- Carbon fibre
- Voice coil
- 2″ QUATTRO in/out aluminium
- Xmax
- ±9 mm
- Motor
- Ceramic (FEA) · Malt Cross® cooling
Beyma T25M
Dome tweeter · 1″
- Dome
- 25.4 mm · aluminium-magnesium
- Impedance
- 4 Ω · minimum 3.3 Ω
- Power
- 20 W AES
- Sensitivity
- 88 dB · 2.83 V / 1 m
- Response
- 1.5 – 30 kHz
- Recommended crossover
- 2.5 kHz · 12 dB/oct
- Motor
- Optimised ceramic (FEA)
Measurements
From the test bench to the semi-anechoic chamber
Measured at Beyma · 08/10/2026
The figures in the spec sheet come from the measurement of one unit of the v11 prototype in Beyma’s semi-anechoic chamber (Moncada, Valencia) on 8 October 2026, at 2.83 V and 1 m. The plots below are earlier: they were taken in an ordinary room, with time gating, on a previous prototype, and are kept here to explain the method.
A loudspeaker is not «tuned by ear». It is measured, corrected and measured again, dozens of times, until the numbers confirm what you are after. That is what separates real design from opinion, and it is how any project that means to reach the market is done.
See the measurement method and the plots
Why a loudspeaker should be as flat as possible
A loudspeaker is, above all, a translator: it turns an electrical signal into sound. Ideally it invents nothing —it gives back every frequency, from the deepest bass to the finest treble, with the same weight it was recorded with. When we plot its frequency response (sound level against frequency), that fidelity shows up as a line as straight and horizontal as possible.
Every deviation from that line is a lie the loudspeaker adds to the music. A peak makes one area —bright treble, swollen bass— sound louder than it should and take over the rest; in time it tires the ear. A dip does the opposite: it buries information that was in the recording and that we will now never hear. A flat loudspeaker is not a «cold» loudspeaker, it is an honest one: the character should come from the recording, the room and your taste, not from a loudspeaker that colours everything the same way.
And it is not enough for the line to be flat right in front of the loudspeaker: what the sound does as it escapes to the sides and bounces around the room matters too (directivity). Toole and Olive showed that a flat on-axis response combined with directivity that falls off smoothly and progressively is, statistically, what listeners prefer in blind tests. That is the target behind every measurement.
The process, in two stages
Preliminary measurements in a real room
Before spending a single euro on an anechoic chamber, the prototype is measured in an ordinary room. The problem is that walls, floor and ceiling send back echoes that dirty the measurement. The answer is not a perfect room but a rigorous method:
- Calibrated measurement microphone. Every mic comes with its own calibration file, which corrects its small imperfections so what it records is faithful to the real sound rather than to the character of the microphone.
- Calibrated sound card. The audio interface is referenced against itself (calibration loop) so neither capture nor playback leaves its own fingerprint on the measurement.
- A computer with REW and time gating. REW (Room EQ Wizard) applies time gating: the response is cut off just before the first wall reflections arrive, so the measurement «sees» only the direct sound of the loudspeaker. It is a «synthetic» anechoic chamber, valid above a certain frequency.
- Equidistant placement, away from walls. Loudspeaker and microphone are placed high up, centred and as far as possible from any surface. The longer the echoes take to arrive, the longer the clean time window and the lower in frequency you can trust the measurement.
With this setup you enter the real working loop: measure, change one crossover value, measure again. Repeated dozens of times, this is what lets you tune the crossover until the target curve falls into place. The bass, where time gating stops being reliable, is measured separately in the near field and spliced onto the rest.
Measurement in Beyma’s semi-anechoic chamber
A semi-anechoic chamber is a room prepared so that sound does not bounce off the walls: the loudspeaker is measured almost as if it were in open space, without the limits of time gating.
On 8 October 2026, Beyma’s engineers measured one unit of the v11 prototype there with a Klippel system: on-axis and 30° response, impedance and distortion. The result: −3 dB at 41 Hz, ±2.3 dB from 50 Hz to 20 kHz on axis, 82.4 dB sensitivity (2.83 V / 1 m), 4 Ω nominal with a 3.9 Ω minimum, and distortion below 0.45 % above 100 Hz. Beyma later repeated the tests and got the same results. Directivity beyond 30° is still to be measured.
Preliminary in-room plots
These plots are from an earlier prototype, measured in-room with time gating. The current figures are those from Beyma’s chamber.
Impedance, for anyone who wants to dig deeper
What impedance is and why we measure it
Impedance is the resistance the loudspeaker offers to the current the amplifier sends it, and it changes with frequency. Measuring it needs no anechoic chamber —an electrical setup with a reference resistor is enough— so, unlike the acoustic curves above, these are already final. These curves, however, come from an earlier prototype; the final system was measured at Beyma. And their shape is an honest X-ray of what happens inside the cabinet: where the woofer resonates, what frequency the port is tuned to, and what load the amplifier you connect will see.
These are electrical measurements of an earlier prototype, with a different volume and tuning. The current figures are Beyma’s: a 3.9 Ω minimum at 8 kHz and port tuning around 35 Hz.
Matching
What to drive it with
It is the question that comes up most often and the one almost no manufacturer answers with numbers. Here they are: the Opus I is an easy load, but not a high-sensitivity loudspeaker, and the measurement in Beyma’s chamber puts numbers on both.
Recommended power
100 W
per channel into 4 Ω, solid state · 60 W or more with valves, from the 4 Ω tap
Any amplifier stable into 4 Ω
The Opus I is rated at 4 Ω nominal, not 8: the 8NMFW woofer is 8 Ω, but the T25M tweeter is 4 Ω and the system minimum with the crossover fitted drops to 3.9 Ω around 8 kHz (measured at Beyma) —a region where music carries very little energy. In the bass, where the amplifier is really asked for current, the load stays above 7 Ω. Any amplifier that claims stability into 4 Ω drives it comfortably, and today that is practically all of them.
How much power it needs
The sensitivity measured at Beyma is 82.4 dB (2.83 V at 1 m), well below the 88 dB of the woofer on its own at that same voltage: that is the price of flat bass down to 41 Hz from a 22-litre cabinet. So the Opus I likes a powerful amplifier: we recommend at least 100 W per channel into 4 Ω, solid state.
Valves, yes, with watts
The load is benign, with no extreme minima, so a valve amplifier drives it without trouble. But at 82 dB you need watts: we recommend at least 60 W per channel, from the 4 Ω tap.
Bi-wiring and bi-amping
The terminal plate has four binding posts: two for the bass and two for the treble. You can bi-wire or bi-amp if you want to explore that. With a single pair of cables, the bass and treble posts must be linked with a jumper.
Gallery
Work in progress
Real photographs of the build process in the workshop. No studio lighting and no retouching: the road from prototype to production.
FaseIdeation
Video
Videos
The build
What to expect if you choose the kit
Building the Opus I is not a carpentry exam. The design is worked out so the result depends on the project and not on the hands of whoever builds it: the layers are numbered and slide down four rods, the crossover arrives assembled and tested, and nothing is glued.
LevelBeginnerno previous experience in carpentry or electronics needed
GlueNonethe body is not glued: it can be opened and closed again
SolderingNonethe crossover arrives assembled, measured and factory-tested
ClampsNot neededthe four M8 rods compress the whole stack on their own
What arrives at your door
«Lira» cabinets
Two boxes, one per loudspeaker: the 23 numbered MDF layers, the baffle and the four M8 rods.
Drivers
Two 8″ Beyma 8NMFW woofers and two Beyma T25M tweeters, in their factory packaging.
Crossovers and hardware
Both crossovers assembled and tested, the hardware sorted into bags by assembly step, the acrylic plates and the printed assembly manual.
The build, step by step
- 01
Stack the layers and fit the crossover
The layers are numbered and slide down the four M8 rods one by one, in order and without glue. The crossover board, which arrives soldered and tested, is screwed onto the third one.
- 02
Tighten the rods
You tighten the four nuts with a 13 mm socket spanner, in two passes: gently first, then firmly. That compression replaces glue and clamps, and closes the joints between layers.
- 03
Connect the terminals and close the baffle
The crossover cables connect to the rear terminal plate with spade terminals: nothing to solder. The baffle is fixed with ten M4 screws over a butyl bead, which makes the seal.
- 04
Mount the drivers
Woofer and tweeter are screwed into their baffle rebates, each with its gasket, and sit flush with the wood. You connect the spade terminals, watching polarity, and close it up.
- 05
Finish it
The cabinet arrives in bare MDF, ready to paint, lacquer or treat. This part is yours: it is where the kit stops being a product and becomes yours.
What you provide
- A 13 mm socket spanner for the M8 rod nuts
- A 3 mm Allen key for all the M4 screws
- A flat screwdriver to align the barrel nuts of the baffle
- Fine sandpaper, only if you are going to lacquer the cabinet yourself
What the kit does not include
- The cabinet finish: paint, lacquer or varnish are down to you (the assembled version does arrive finished).
- The speaker cable to your amplifier.
- The amplifier. There is a guide below on what to drive it with.
Open source
Materials for the community
We believe in shared knowledge. The crossover schematic, the component list and the driver data sheets can be downloaded here.
Crossover schematic
Passive crossover with Jantzen Audio and Dayton Audio components.
Driver specifications
Official Beyma datasheets for the drivers in the kit.
How to get one
Two ways to own the Opus I
The Opus I will come in two formats: the Kit, to build it yourself and get to know the loudspeaker from the inside, or the assembled, lacquered version, ready to play.
In preparation First series
Made to order
The first series of the Opus I is in preparation. Leave us your contact details and we will let you know as soon as it can be reserved.
Option 1 · Kit
As a kit, to build at home
You get the Opus I in four boxes and assemble it yourself, with the step-by-step manual.
- Four boxes, about 46 kg in total: the layers for both cabinets, the Beyma drivers, the crossovers already assembled and tested, and the hardware.
- A printed, step-by-step assembly manual, with the hardware sorted into bags by step.
- The layers of each cabinet arrive numbered, except the base, and slide down four rods in the marked order: nothing is glued.
- The cabinet is delivered in raw MDF, unfinished: you finish it yourself, at home, the way you like it.
- The cheapest route, and the one that lets you understand the loudspeaker from the inside.
Option 2 · Assembled
Assembled and finished
You receive the pair assembled and lacquered in white, ready to place and connect.
- Cabinets, drivers and crossovers assembled, adjusted and tested in the workshop.
- White lacquer finish, with a black baffle.
- Nothing to build: they arrive ready to put in place and enjoy.
Or buy the modules separately
If you already own part of the system or prefer to build part of it yourself, the cabinet and the crossover will also be offered separately.
Opus I cabinetThe pair of cabinets as a kit: the 23 layers of each loudspeaker and the baffle, in CNC-machined MDF, unfinished.Coming soon
Opus I crossover, assembledThe pair of passive crossovers, assembled and tested.Coming soon
Opus I crossover componentsThe Jantzen Audio and Dayton Audio components for both crossovers, to solder yourself.Coming soon
Questions
Frequently asked questions
Where does the project stand?
The first series of the Opus I is in preparation. It will come in two formats: assembled and lacquered, or as a kit. The design is that of the first series —the «Lira» cabinet, the Beyma drivers and the crossover you see in the specs— and one unit of the v11 prototype was measured in Beyma’s semi-anechoic chamber on 8 October 2026. It will be made to order. You can follow the state of the project on the timeline at the top of this page.
What finish does it have?
It depends on the format. The images of the lacquered version on this page are simulations, not photographs.
- Opus I Kit: it is delivered in raw MDF, unfinished, so you can finish it at home the way you like.
- Opus I assembled: it is lacquered in white, with a black baffle.
What if I build it wrong?
That is the reasonable worry of anyone considering a kit, and the design is built around it: the layers are numbered, except the base, and slide down the four rods in the marked order. The crossover arrives assembled and tested, so there is nothing to solder and nothing to calculate. Because the body is not glued, a mistake can be put right: you loosen the nuts, reposition the layer and tighten again. And if you get stuck, you write straight to the designer: there is no customer service department in between.
Do I need to be a carpenter or know electronics?
No. The build needs no soldering, no glue, no clamps and no special tools: a 13 mm socket spanner, a 3 mm Allen key and a screwdriver are enough. The «The build» section on this page has the detail on tools and what is in each box.
Where is it designed and manufactured?
The Opus I is designed in Barcelona and the drivers are from Beyma, who design and manufacture in Moncada (Valencia). The CNC machining of the cabinet is done by Nord Taller, a craft workshop, and the lacquering in a workshop in the Barcelona area.
Does it come with a warranty?
Yes, the 3-year legal warranty. And since it is hand-made by its author, anything that comes up is dealt with directly, with no middlemen.
Public presentation
September 2026
The Opus I was first shown in public at the Stereo Vintage Barcelona fair. If you want to hear about the next listening sessions, leave me your contact details.
Community
Questions and answers
The channel is open to discuss simulations, suggest changes or sort out technical questions directly with the designer.
Join the Opus I community
Come into the project group to follow the build, share your own progress and sort out technical questions directly with the designer.
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